1. Field of the Invention
The present invention relates to a process of aldol condensation of an active hydrogen-containing compound by a gas-phase reaction in the presence of a fixed bed solid catalyst.
2. Description of the Related Art
Processes of aldol condensation have been disclosed in Japanese Unexamined Patent Publication Nos. 52-113390 (corresponding to U.S. Pat. No. 4,086,188), 58-219139 and 60-172349 in which aldol condensation of an active hydrogen-containing compound is carried out by a gas-phase reaction in the presence of a fixed bed solid catalyst and wherein vaporization of a liquid of the active hydrogen-containing compound is carried out before the catalyst bed in a reactor. However, these processes have a disadvantage that the design of the reactor becomes complex since the vapor flow of the active hydrogen-containing compound is heated by 3/4 inch-high temperature glass fiber insulated tapes which were controlled by temperature controllers. Thus, these processes are not necessarily satisfactory from the viewpoint of the reaction in a commercial scale.